The Portland area is in for at least one more night of temperatures in the low 20s or high teens and then the drip, drip, drip of the big thaw might be on. (At least before the of snow arrives. ) That could mean that two costly problems become apparent in the next day or two: Ice dams and burst pipes. First, ice dams. Ice dams are masses of ice that form along the edges of rooftops when snow on poorly insulated homes melts, rolls down the rooflines and then refreezes near the homes’ eaves. Their presence is often accompanied by icicles, sometimes massive ones. As outdoor temperatures warm, water pools under the ice dam and can be pushed back under shingles – leading to water leaking into homes, soaking insulation, staining ceilings, warping floors, causing mold and mildew problems and damaging belongings inside. The damage can soar into the thousands of dollars. Ice dams don’t frequently form in the Portland area like they do in some other parts of the country because the conditions that create them – heavy accumulations that don’t quickly melt because of a prolonged cold spell – rarely exist in the Willamette Valley. But a quick tour of homes in Portland reveals that this week’s storm presented the right conditions. So what should homeowners do? If ice dams have already formed, professional maintenance companies can remove them. Homeowners also can attempt to lessen their impact by using a long roof rake to pull snow off their roofs while standing on the ground. Some experts also recommend filling up tube socks or nylon stocking with calcium chloride, then placing them vertically on the ice dams to create a channel where water from the melted ice will flow off the roof. When outside temperatures warm, keep watch on your home’s attic, ceilings, walls and floors – including under large pieces of furniture – for water that might be leaking in. Fix-it guy Bob Vila on how to prevent and respond to ice dams. The other big home headache that this week’s cold spell could have caused are frozen pipes. Pipes freeze because they’re not well-insulated or they’re in poorly insulated spaces – typically garages, crawl spaces or attics. One trick to prevent them from freezing is to run a trickle of water from a home’s taps. Opening cabinets or closets with pipes to let the heat in also can help prevent them from freezing. If your pipes have already frozen, you might realize this when you turn your faucet on and nothing comes out. The problem also might become obvious when outside temperatures warm and water from burst pipes starts flooding homes. If your pipes freeze, shut off the main water valve to your home and then open the faucets inside and outside your home to prevent pressure from building up. Not all frozen pipes will burst. Also be aware that you might need professional help because some pipes burst in areas – such as walls or floors – where a home’s occupants can’t see them. The American Red Cross on what to do if your pipes freeze. -- Aimee Green; ; @o_aimee.